SQL> select * from ddd; COLA
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500已选择7行。已用时间: 00: 00: 00.03
SQL> select cola from ddd group by cola having count(1) > 1; COLA
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500已选择7行。已用时间: 00: 00: 00.03
SQL> select cola from ddd group by cola having count(1) > 1; COLA
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( select count(*) from table t2 where t1.colname = t2.colname having count(*) > 1 )